Four bar drive mechanism for bleed system

Abstract

An actuation system for a bleed valve includes first and second bell cranks connected by a connecting link. The first bell crank has a first arm that is coupled to a bleed valve and a second arm that is coupled to the connecting link. The connecting link has a first end coupled to the second arm of the first bell crank and a second end coupled to a first arm of the second bell crank. A second arm of the second bell crank is coupled to an actuating element. Input is communicated through the actuating element to move the bleed valve between open and closed positions via the first and second bell cranks.

What is claimed is: 
     
       1. An actuation system for a bleed valve comprising:
 a first bell crank having a first arm and a second arm, the first arm being coupled to a bleed valve; 
 a connecting link having a first end and a second end, the first end being coupled to the second arm of the first bell crank; and 
 a second bell crank having a first arm and a second arm, the first arm being coupled to the second end of the connecting link and the second arm being coupled to an actuating element, and wherein input is communicated through the actuating element to move the bleed valve between open and closed positions via the first and second bell cranks. 
 
     
     
       2. The actuation system of  claim 1  wherein the first bell crank is positioned on one side of the bleed valve and the second bell crank is positioned on an opposite side of the bleed valve. 
     
     
       3. The actuation system of  claim 2  wherein the connecting link extends over an outer radial surface of the bleed valve to connect the first and second bell cranks. 
     
     
       4. The actuation system of  claim 3  wherein the second arm of the first bell crank is radially outward of the first arm of the first bell crank. 
     
     
       5. The actuation system of  claim 3  wherein the first arm of the second bell crank is radially outward of the second arm of the second bell crank. 
     
     
       6. The actuation system of  claim 3  wherein the second arm of the first bell crank is radially outward of the first arm of the first bell crank, and wherein the first arm of the second bell crank is radially outward of the second arm of the second bell crank. 
     
     
       7. The actuation system of  claim 1  wherein the first and second arms of the first bell crank are separated from each other by an obtuse angle. 
     
     
       8. The actuation system of  claim 7  wherein the first and second arms of the second bell crank are separated from each other by an acute angle. 
     
     
       9. The actuation system of  claim 1  wherein the first and second arms of the first bell crank are separated from each other by a first radial distance and wherein the first and second arms of the second bell crank are separated from each other by a second radial distance greater than the first radial distance. 
     
     
       10. The actuation system of  claim 1  including a first mount coupled to the first bell crank to define a first pivot and a second mount coupled to the second bell crank to define a second pivot. 
     
     
       11. The actuation system of  claim 10  wherein the first mount is configured for attachment to a casing in a compressor section and the second mount is configured for attachment to a bleed duct case. 
     
     
       12. The actuation system of  claim 11  including a bridge plate connecting the first and second mounts. 
     
     
       13. A bleed valve assembly for a compressor section of a gas turbine engine comprising:
 a bleed valve movable between an open and a closed position; 
 a bleed duct case including a plurality of passages, wherein the bleed valve engages the bleed duct case to close the plurality of passages when in the closed position and moves away from the bleed duct case to uncover the plurality of passage when in the open position; 
 a first bell crank having a first arm and a second arm, the first arm being coupled to the bleed valve; 
 a connecting link having a first end and a second end, the first end being coupled to the second arm of the first bell crank; and 
 a second bell crank supported by the bleed duct case and having a first arm and a second arm, the first arm being coupled to the second end of the connecting link and the second arm being coupled to an actuating element, and wherein input is communicated through the actuating element to move the bleed valve between the open and closed positions via the first and second bell cranks. 
 
     
     
       14. The bleed valve assembly of  claim 13  wherein the first and second arms of the first bell crank are separated from each other by an obtuse angle. 
     
     
       15. The bleed valve assembly of  claim 14  wherein the first and second arms of the second bell crank are separated from each other by an acute angle. 
     
     
       16. The bleed valve assembly of  claim 13  wherein the first and second arms of the first bell crank are separated from each other by a first radial distance and wherein the first and second arms of the second bell crank are separated from each other by a second radial distance greater than the first radial distance such that the connecting link extends between the first and second bell cranks at a radially outward position relative to the bleed valve and bleed duct case. 
     
     
       17. The bleed valve assembly of  claim 13  including a first mount coupled to the first bell crank to define a first pivot and a second mount coupled to the second bell crank to define a second pivot, wherein the first mount is fixed to a casing in a compressor section and the second mount is fixed to the bleed duct case. 
     
     
       18. The bleed valve assembly of  claim 17  including a fire wall that is fixed to the casing, and including a stand-off mounted to one side of the fire wall and a spool mounted to the stand-off, and wherein the actuating element comprises an actuating link that extends through the stand-off and spool to connect to an actuating mechanism. 
     
     
       19. The bleed valve assembly of  claim 18  wherein the spool comprises a cylinder. 
     
     
       20. The bleed valve assembly of  claim 17  including a bridge plate connecting the first and second mounts. 
     
     
       21. The actuation system of  claim 1  wherein the second arm of the first bell crank is actuated by the actuating element via the second bell crank and connecting link.